CN101006211A - Inorganic fiber, fiber structure and method for producing same - Google Patents

Abstract

The invention relates to an inorganic fibers consisting substantially of silicon, carbon, oxygen and a transition metal, having a fiber size of no greater than 2 [mu]m and having fiber lengths of 100 [mu]m or greater.

Description

Inorganic fiber, fiber structure and manufacturing method thereof

technical field

The present invention relates to an inorganic fiber, and more specifically relates to an inorganic fiber with a small fiber diameter, a fiber structure and a manufacturing method thereof.

Background technique

In recent years, silicon-containing polymers have attracted attention as functional materials such as heat-resistant materials, optical functional materials, and ceramic materials.

Inorganic fibers including silicon-containing polymers developed so far have excellent heat resistance and mechanical properties compared with other materials, so they can be used under severe conditions, such as aircraft and anti-pollution substrates. As these inorganic fibers, for example, silicon carbide fibers (manufactured by Japan (カ一ボン) Co., Ltd., trademark: NIKALON), silicon-titanium-carbon-oxygen fibers (manufactured by Ube Yosan Co., Ltd., trademark: Tirano Fibers) are proposed. etc. (see Patent Document 1 and Non-Patent Document 1).

In particular, silicon-titanium-carbon-oxygen fibers have photocatalytic activity and can be used for decomposition of dioxins or for sterilization (see Non-Patent Document 1).

However, the fiber diameter of this fiber is limited to 5 to 8 μm, so the surface area of the fiber exhibiting photocatalytic activity is insufficient. In addition, when these inorganic fibers are used as filters, fibers with a larger surface area are required, so finer fibers are required.

Recently, nonwoven fabrics containing inorganic fibers having photocatalytic ability have been proposed (see Patent Documents 2 and 3). However, the average fiber diameter of the fibers obtained by this production method is about 5 μm, and it is difficult to produce inorganic fibers with a diameter of 2 μm or less by a production technique such as the meltblown method (Meltblown method). In addition, since the obtained fibers are limited to smooth fibers, there is also a problem that the specific surface area cannot be increased.

On the other hand, as a method of producing fine inorganic fibers, a method of introducing a sol solution into an electric field, spinning, and then sintering has been proposed (Patent Document 4). The diameter of the fiber obtained by this method is as small as 2 μm or less, but it is difficult to make the fiber have photocatalytic activity by this production method. In addition, the obtained fiber is glass in nature, so the heat resistance is insufficient.

[Patent Document 1] Japanese Unexamined Publication No. 7-189039

[Patent Document 2] JP-A-2004-60095

[Patent Document 3] JP-A-2004-60096

[Patent Document 4] JP-A-2003-73964

[Non-Patent Document 1] Toshihiro Ishikawa, "High-Strength Titanium OxideFivers", published by Industrial Materials, Nikkan Kogyo Shimbun, July 2002, Vol. 50, Pages 48-51

Contents of the invention

The object of the present invention is to solve the problems in the prior art mentioned above, and provide a fiber containing silicon, carbon, oxygen and transition metals with extremely small fiber diameter.

In addition, another object of the present invention is to provide a fibrous structure containing the above-mentioned fibers.

A further object of the present invention is to provide a method for producing the above-mentioned fibrous structure in an extremely simple manner.

Description of drawings

Fig. 1 is a schematic view of one embodiment of the apparatus structure for producing the ultrafine fiber structure of the present invention.

Fig. 2 is a schematic diagram of one embodiment of an apparatus structure for producing the ultrafine fiber structure of the present invention.

FIG. 3 is a photograph (800 times) of the surface of the calcined fiber structure obtained in Example 1 with a scanning electron microscope.

4 is a photograph (20,000 times) of the surface of the calcined fiber structure obtained in Example 1 with a scanning electron microscope.

FIG. 5 is a photograph (20,000 times) of the surface of the calcined fiber structure obtained in Example 2 with a scanning electron microscope.

6 is a photograph (20,000 times) of the surface of the calcined fiber structure obtained in Example 3 with a scanning electron microscope.

FIG. 7 is a photograph (400 times) of the surface of the calcined fiber structure obtained in Example 4 with a scanning electron microscope.

8 is a photograph (20,000 times) of the surface of the calcined fiber structure obtained in Example 4 with a scanning electron microscope.

FIG. 9 is a photograph (400 times) of the surface of the calcined fiber structure obtained in Example 5 with a scanning electron microscope.

10 is a photograph (20,000 times) of the surface of the calcined fiber structure obtained in Example 5 with a scanning electron microscope.

FIG. 11 is a photograph (20,000 times) of the surface of the calcined fiber structure obtained in Comparative Example 3 with a scanning electron microscope.

Detailed ways

The present invention will be described in detail below.

The fiber diameter of the inorganic fibers composed of silicon, carbon, oxygen, and transition metals of the present invention must be 2 μm or less, and the fiber length must be 100 μm or more.

If the fiber diameter exceeds 2 μm, the stiffness of the fiber increases and becomes brittle. Therefore, for example, when used in a filter application, the fiber may be broken and cause secondary pollution, and the handleability may deteriorate. In addition, since the specific surface area becomes too small, for example, when titanium having photocatalytic ability is used as a transition metal as described later, there is a disadvantage that the effective utilization part decreases based on the amount of titanium present, so it is not preferable. . The fiber diameter is preferably 0.01 to 1.5 μm, more preferably 0.05 to 1 μm. In addition, when there are no recesses described later on the fiber surface, the fiber diameter is preferably 1 μm or less.

If the fiber length is less than 100 μm, the mechanical strength of the resulting fiber structure will be insufficient. The fiber length is preferably 150 μm or more, more preferably 1 mm or more.

As the transition metal present in the inorganic fiber of the present invention, titanium and zirconium are preferable because they can impart photocatalytic ability, or can exhibit sufficient mechanical properties and corrosion resistance. The molar ratio of silicon to transition metal is not particularly limited as long as the necessary properties can be expressed, but it is preferably in the range of 100/1 to 1/10 because the obtained fibers have good mechanical properties.

In addition, "inorganic fiber" in the present invention refers to a fiber having an organic compound content of not more than 5% by weight.

The fiber of the present invention preferably has concave portions with a diameter of 0.01 to 0.5 μm on its surface. If the diameter of the concave portion is less than 0.01 μm, the surface area becomes small, which is not preferable; if it exceeds 0.5 μm, the mechanical properties of the fiber will be significantly reduced, which is not preferable. The diameter of the concave portion is more preferably 0.02 to 0.5 μm.

Regarding the surface structure of the fiber of the present invention, it is preferable that the recesses account for 10 to 95% of the fiber surface. If the ratio of the concave portion to the surface is 10% or less, the surface area of the fiber becomes smaller, which is not preferable; if it is 95% or more, the mechanical properties of the fiber are reduced, which is not preferable. The ratio of the concave portion to the surface is preferably 20 to 80%.

The fiber structure of the present invention contains at least the fibers containing silicon, carbon, oxygen, and transition metals of the present invention. Here, the "fibrous structure" in the present invention refers to a three-dimensional structure formed by fibers through operations such as weaving, braiding, and lamination. body, non-woven fabrics are mentioned as a preferable example. In this fiber structure, it is preferable that the fibers containing silicon, carbon, oxygen, and transition metals of the present invention account for 100%.

When producing the fibrous structure of the present invention, any method that can obtain the above-mentioned fibrous structure can be used, but as a preferred embodiment, a production method including the following steps can be cited: the above-mentioned organosilicon-based polymer, fiber-forming organic A step of preparing a solution by dissolving the polymer and a transition metal compound; a step of spinning the above solution by electrospinning; obtaining a fiber structure accumulated on the collecting electrode substrate (collecting electrode substrate) by the above spinning, A step of producing a precursor ultrafine fiber structure; a step of making the above ultrafine fiber structure infusible to obtain an infusible ultrafine fiber structure; and a step of calcining the infusible ultrafine fiber structure to obtain a ceramic ultrafine fiber structure .

The organosilicon polymer of the present invention is not particularly limited, for example, polycarbomethylsilane (polycarbomethylsilane), polytitanocarbosilane (polytitanocarbosilane), polyzirconocarbosilane (polyzirconocarbosilane), polybororodiphenylsiloxane ( polyborodiphenylsiloxane), polydimethylsilane, etc.

Among these, silicone-based polymers containing a repeating unit represented by the following general formula (1) are preferred from the viewpoint of spinning safety, and polycarbomethylsilane is particularly preferred. Most preferred are polycarbomethylsilanes having a molecular weight of 500 or greater.

(R and R' in the formula are independently selected from a hydrogen atom, a lower alkyl group with 1 to 10 carbon atoms, and a phenyl group)

The organic polymer in the present invention is not particularly limited as long as it is soluble in a solvent and exhibits a viscosity that can be spun by electrospinning, for example, polyethylene glycol (polyethylene oxide), Polyoxypropylene, polyethylene glycol (polyoxyethylene)-polyoxypropylene block copolymer, polycyclopentene oxide, polyvinyl chloride, polyacrylonitrile, polylactic acid, polyglycolic acid, polylactic acid - Copolymer polyacetate, polycaprolactone, polybutylene succinate, polyethylene succinate, polystyrene, polycarbonate, polyhexylene carbonate, polyacrylate, polyvinyl isocyanate, poly Butyl isocyanate, polymethyl methacrylate, polyethyl methacrylate, poly-n-propyl methacrylate, poly-n-butyl methacrylate, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate , Polyethylene terephthalate, Polypropylene terephthalate, Polyethylene naphthalate, Poly(p-phenylene terephthalamide), Poly(p-phenylene terephthalamide-3) , 4'-Oxydiphenylene terephthalamide (oxydiphenylene terephthalamide) copolymer, polym-phenylene isophthalamide, cellulose diacetate, cellulose triacetate, methyl cellulose, propyl cellulose , benzyl cellulose, silk fibroin, natural rubber, polyvinyl acetate, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl n-propyl ether, polyvinyl isopropyl ether, polyethylene n-butyl ether, polyvinyl isobutyl ether, polyvinyl tert-butyl ether, polyvinylidene chloride, poly(N-vinylpyrrolidone), poly(N-vinylcarbazole), poly(4-vinyl pyridine), polyvinyl methyl ketone, polymethyl isopropenyl ketone, polystyrene sulfone (polystyrene sulfone), nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612 and their copolymers or Polymer blends, etc.

Among them, polyethylene glycol (polyoxyethylene), polypropylene oxide, and block copolymers of polyethylene glycol (polyoxyethylene)-polyoxypropylene are preferred, and polyethylene glycol is more preferred.

Polyethylene glycol with a molecular weight of 50,000 or more is particularly preferred, and polyethylene glycol with a molecular weight of 100,000 to 8 million is most preferred.

The transition metal in the present invention is not particularly limited, but titanium and zirconium are preferable because they can impart photocatalytic ability and can express sufficient mechanical properties and corrosion resistance. If the transition metal is present in the solution, although its role is not clear, in the electrospinning method, fibers with a fiber diameter of 2 μm or less can be efficiently produced.

Here, the electrospinning method refers to a method in which a solution in which a fiber-forming compound is dissolved is discharged into an electrostatic field formed between electrodes, the solution is drawn toward the electrodes, and the formed fibrous substances are accumulated on the collecting substrate, Thus, the method of obtaining a fibrous structure, the fibrous substance here means not only the state in which the solvent dissolving the fibrous compound is distilled off to form a fibrous substance, but also the state in which the solvent is contained in the fibrous substance.

Next, an apparatus used in the electrospinning method will be described.

The above-mentioned electrode may be any of metal, inorganic or organic, as long as it exhibits conductivity, and may be an electrode having a conductive metal, inorganic or organic thin film on an insulator.

In addition, an electrostatic field is formed between a pair or a plurality of electrodes, and a high voltage can be applied to any one of the electrodes. This includes, for example, the case of using two high-voltage electrodes with different voltage values (for example, 15 kV and 10 kV) and the electrode connected to the ground line, a total of three electrodes, or the case of using more than three electrodes.

Next, a method for producing the fibers constituting the fiber structure of the present invention by the electrospinning method will be described in order.

First, a solution is prepared by dissolving the silicone-based polymer, the fiber-forming organic polymer and the transition metal compound. Here, the concentration of the fiber-forming organic polymer in the solution is preferably 0.05-20% by weight or 0.05-20% by weight or more. If the concentration is less than 0.05% by weight, since the concentration is too low, it becomes difficult to form a fibrous structure, which is not preferable. Moreover, if it exceeds 20 weight%, the average diameter of the fiber obtained may become large, and viscosity may become large, and electrospinning may become difficult. A more preferable concentration is 0.1 to 10% by weight.

The concentration of the silicone-based polymer in the solution is preferably 0.1 to 50% by weight. If the concentration is less than 0.1% by weight, the mechanical strength of the obtained fibrous structure will decrease, which is not preferable. Moreover, if it exceeds 50 weight%, it will become difficult to obtain a fiber structure, and it is unpreferable. More preferably, it is 1 to 30% by weight.

The concentration of the transition metal compound in the solution is preferably 0.1 to 50% by weight. If the concentration is less than 0.1% by weight, the mechanical strength of the obtained fibrous structure will decrease, which is not preferable. Moreover, if it exceeds 50 weight%, it will become difficult to obtain a fiber structure, and it is unpreferable. More preferably, it is 1 to 30% by weight.

In addition, as the solvent for dissolving the above-mentioned silicone-based polymer and organic polymer, as long as it can dissolve the fiber-forming organic polymer, and can be evaporated in the spinning step of the electrospinning method to form fibers, It is not particularly limited, but a nonpolar solvent is preferable from the viewpoint of the solubility of the above-mentioned silicone-based polymer. As this solvent, methylene chloride, chloroform, carbon tetrachloride, cyclohexane, benzene, toluene, trichloroethane etc. are mentioned, for example. Among them, halogen-based solvents are preferable, and dichloromethane is particularly preferable. In addition, these solvents may be used alone or in combination of a plurality of solvents may be used as a mixed solvent.

In addition, especially in the electrospinning method, since the viscosity of the solution and the evaporation rate of the solvent have a great influence on the average diameter of the formed fibers, a polar solvent as a regulator can also be added in addition to the above solvents, such as: Acetone, ethanol, isopropanol, methanol, butanol, tetrahydrofuran, benzyl alcohol, 1,4-dioxane, propanol, cyclohexanone, phenol, pyridine, acetic acid, N,N-dimethylformamide, N , N-dimethylacetamide, acetonitrile, N-methylpyrrolidone, N-methylmorpholine-N-oxide, 1,3-dioxolane, methyl ethyl ketone, etc.

The procedure for spinning the above solution by the electrospinning method will be described below. Any method can be used to discharge the solution into the electrostatic field, for example, by supplying the solution to a nozzle, placing the solution at an appropriate position in the electrostatic field, and drawing the solution from the nozzle through the electric field to form fibers. In addition, the solution temperature at this time is not particularly limited, but it is usually from 0° C. to the boiling point of the solvent, and spinning can be easily performed at room temperature. The relative humidity is not particularly limited either, but it is preferable to have a relative humidity of 10 to 70% because the stability during electrospinning is good, and a relative humidity of 20 to 60% is particularly preferable. By controlling the discharge time, voltage, and spinning distance, the basis weight and film thickness of the obtained fiber structure can be arbitrarily controlled.

Hereinafter, it will be described in more detail with reference to FIG. 1 .

Appropriate devices are provided at the front end of the cylindrical solution holding tank (3 in FIG. 1 ) of the syringe, such as an injection needle-shaped solution ejection nozzle (1 in FIG. 1 ) to apply a voltage by a high voltage generator (6 in FIG. 1 ). ), guide the solution (2 in Figure 1) to the front end of the solution ejection nozzle. Configure the front end of the solution ejection nozzle (1 in Fig. 1) at an appropriate distance from the grounded fibrous matter collecting electrode (5 in Fig. 1), so that the solution (2 in Fig. 1) is ejected from the solution nozzle (Fig. 1) is sprayed from the tip of 1), and fibrous substances can be formed between the tip of the nozzle and the fibrous substance collecting electrode (5 in FIG. 1). At this time, it is more preferable to place a mask (7 in FIG. 1 ) on the fibrous substance collecting electrode (5 in FIG. 1 ), since it is possible to efficiently produce ultrafine fibers of a desired shape. As a mask, a mask containing an organic polymer having a dielectric constant of 2.4 or more is effective. In addition, as another way, using FIG. 2 to illustrate, the fine droplets (not shown) of the solution can be introduced into the electrostatic field. The only condition at this time is: the solution (2 in FIG. 2) is placed in the electrostatic field In the process, keep the fibrous material collecting electrode (5 in Fig. 2) at a distance where fibrosis can occur. For example, the electrode (4 in FIG. 2 ) opposed to the fibrous substance collecting electrode can be directly inserted into the solution (3 in FIG. 2 ) in the solution holding tank (3 in FIG. 2 ) having the solution ejection nozzle (1 in FIG. 2 ). 2) in.

Furthermore, the diameter of the spinning nozzle is not particularly limited, but is more preferably in the range of 50 to 1000 μm. The nozzle is not limited to one, and two or more nozzles may be used. In addition, the material of the nozzle may be metal or non-metal.

Furthermore, if the nozzle is made of metal, it can be used as an electrode, and if it is made of non-metal, a voltage can be applied by providing an electrode inside. By increasing the number of nozzles and increasing the supply rate of the solution, productivity can be greatly improved. In addition, the distance between the electrodes is related to the amount of charge, the size of the nozzle, the amount of solution ejected from the nozzle, and the concentration of the solution. When the voltage is about 10 kV, a distance of 5 to 20 cm is appropriate. In addition, the applied electrostatic potential is usually 3 to 100 kV, preferably 5 to 50 kV, more preferably 5 to 35 kV. The desired potential can be achieved by any appropriate conventionally known method.

The above-mentioned two methods are the case where the electrodes also serve as the collection substrate, and it is also possible to arrange an object that can serve as the collection substrate between the electrodes, so that the electrodes and the collection substrate are separately provided, and the fiber laminate is collected thereon. In this case, for example, a strip-shaped substance can be provided between electrodes, and it can be used as a collection substrate, and it can be produced continuously.

Next, the procedure for obtaining the fibrous structure accumulated on the collecting substrate will be described. In the present invention, in the process of drawing the solution toward the collecting substrate, the solvent evaporates depending on the conditions to form a fibrous substance. If the solvent is completely evaporated before being captured on the capture substrate at normal room temperature, but if the solvent is not evaporated sufficiently, the wire can also be drawn under reduced pressure. When collected on the collection substrate, a fiber structure that satisfies at least the above average fiber diameter and fiber length is formed. In addition, the drawing temperature is related to the evaporation behavior of the solvent or the viscosity of the spinning solution, and is usually in the range of 0-50°C.

In the present invention, the organosilicon-based polymer and the transition metal compound are drawn by the above-mentioned method, and then infused. As a method of making the fiber structure obtained by spinning insoluble, a known method can be used, for example, a method of heating the fiber structure at a temperature in the range of 50 to 400° C. in an oxidizing gas atmosphere, or using gamma rays or A method of irradiating a fiber structure obtained by spinning with an electron beam.

The spun and infusible fiber structure is fired in an oxygen atmosphere, an inert gas atmosphere such as nitrogen or argon, or in a vacuum.

The highest calcination temperature is a temperature in the range of 800 to 2000°C, preferably a temperature in the range of 1000 to 1600°C. If it is higher than 2000° C., rapid crystallization of silicon carbide and evaporation of silicon carbide will occur, resulting in a significant decrease in the strength of the obtained inorganic fiber.

The fiber structure obtained by the manufacturing method of the present invention can be used alone, or can be used in combination with other materials in consideration of operability or other requirements. For example, using a metal mesh, non-woven fabric, woven cloth, film, etc. that can be used as a support base as a collection substrate, by forming a fiber laminate thereon, a combination of the support base and the fiber laminate can be made. made of material.

Example

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited by these examples. In addition, each value in an Example was calculated|required by the following method.

(1) The average diameter of the fiber:

The surface of the obtained fiber structure was photographed by a scanning electron microscope (manufactured by Hitachi, Ltd. S-2400) (magnification: 8000 times), and 20 places were randomly selected from the obtained photograph to measure the fiber diameter and obtain the total fiber diameter (n=20 ) as the average diameter of the fibers.

(2) Confirm the presence of fibers with a fiber length of 100 μm or less:

The surface of the obtained fiber structure was photographed with a scanning electron microscope (manufactured by Hitachi, Ltd. S-2400) (magnification: 400 times or 800 times), and the obtained picture was observed to confirm whether there were fibers with a fiber length of 100 μm or less.

(3) Confirm the presence of concave portions on the fiber surface:

The surface of the obtained fibrous structure was photographed with a scanning electron microscope (S-2400 manufactured by Hitachi, Ltd.) (magnification: 20,000 times), and the obtained photograph was observed. The diameter of the concave portion was measured from the photograph, and the average value was calculated (n=20).

In addition, the proportion of the concave portion occupied on the fiber surface was measured, and the average value was calculated (n=5).

Example 1

A mixture containing 8 parts by weight of polycarbomethylsilane (molecular weight: 3500; manufactured by Aldrich), 0.1 part by weight of polyethylene glycol (molecular weight: 4 million; manufactured by Wako Pure Chemical Industries, Ltd.), methylene chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was prepared. , special grade) 83.9 parts by weight, and a solution of 8 parts by weight of tetrabutoxytitanium (manufactured by Wako Pure Chemical Industries, Ltd.). Then, using the apparatus shown in FIG. 1 , the solution was discharged to the collecting electrode (5 in FIG. 1 ) for 10 minutes. The inner diameter of the discharge nozzle (1 in FIG. 1 ) was 0.5 mm, the voltage was 12 kV, and the distance from the discharge nozzle 1 to the fibrous substance collecting electrode 5 was 15 cm. The obtained fibrous structure was in the form of a nonwoven fabric.

Place the obtained fiber structure in air at 70°C for 100 hours, raise the temperature to 200°C (heating rate: 10°C/min), keep it for 1 hour, then raise the temperature to 1000°C (heating rate: 2°C/min), keep 3 hours, let cool to room temperature. The obtained fiber structure had flexibility, the average fiber diameter was 0.9 μm, the average diameter of the concave portion on the fiber surface was 54 nm, and the ratio of the area of the concave portion to the fiber surface was 53%. As a result of measuring the obtained fibrous structure with a scanning electron microscope, no fibers having a fiber length of less than 100 μm were observed. The scanning electron micrographs of the surface of the obtained fiber structure are shown in Fig. 3 and Fig. 4 .

The resulting fiber structure was cut into 2 cm in length and 2 cm in width, and immersed in 5 ml of a 10 ppm methylene blue aqueous solution. The solution became completely transparent when irradiated with light in the range of 295 to 450 nm at an intensity of 60 mW/cm ² for 30 minutes using an Eye Super UV detector "SUV-F11" manufactured by Iwasaki Electric Co., Ltd. This shows that the obtained fiber structure has photocatalytic activity.

Example 2

In Example 1, polyethylene oxide (molecular weight: 200,000; manufactured by Aldrich) was used instead of polyethylene glycol (molecular weight: 4,000,000; manufactured by Wako Pure Chemical Industries, Ltd.) in the spinning dope, and the same operation was performed except that A non-woven fabric-like fibrous structure is formed.

The same operation as in Example 1, the obtained fiber structure was subjected to the non-melting and calcining process, the obtained fiber structure had flexibility, the average fiber diameter was 1.0 μm, the average diameter of the concave portion on the fiber surface was 70 nm, and the area of the concave portion accounted for 10% of the fiber surface. The ratio is 32%.

This nonwoven fabric-like fibrous structure was formed. When the obtained fiber structure was measured with a scanning electron microscope ("S-2400" manufactured by Hitachi, Ltd.), fibers with a fiber length of less than 100 µm were not observed. A scanning electron micrograph of the surface of the obtained fiber structure is shown in FIG. 5 .

Example 3

In Example 1, 8 parts by weight of polycarbomethylsilane (molecular weight 3500, manufactured by Aldrich) and 8 parts by weight of tetrabutoxyzirconium (80% butanol solution; manufactured by Wako Pure Chemical Industries, Ltd.) were used as the spinning stock solution. , a solution of 0.1 parts by weight of polyethylene glycol (molecular weight: 4 million, manufactured by Wako Pure Chemical Industries, Ltd.), and 181.9 parts by weight of methylene chloride (manufactured by Wako Pure Chemical Industries, Ltd., special grade), except that the same operation was carried out , forming a non-woven fiber structure. The resulting fibrous structure was kept in air at 90° C. for 16 hours, then raised to 200° C. (heating rate of 10° C./minute), kept at this temperature for 3 hours, and then heated at 2° C./minute in a nitrogen atmosphere. The heating rate is to raise the temperature to 1000°C, and then return to room temperature. The obtained fiber structure has flexibility, the average fiber diameter is 0.8 μm, the average diameter of the concave portion on the fiber surface is 80 nm, and the ratio of the area of the concave portion to the fiber surface is 25%. When the obtained fiber structure was measured with a scanning electron microscope ("S-2400" manufactured by Hitachi, Ltd.), fibers with a fiber length of less than 100 µm were not observed. A scanning electron micrograph of the surface of the obtained fiber structure is shown in FIG. 6 .

Example 4

A nonwoven fabric-like fibrous structure was formed in the same manner as in Example 1, except that 0.05 parts by weight of polyethylene glycol was used, and the distance from the discharge nozzle 1 to the fibrous substance collecting electrode 5 was 20 cm.

In the same manner as in Example 1, the resulting fibrous structure was subjected to non-melting and calcining steps. The resulting fibrous structure had flexibility and an average fiber diameter of 0.7 μm.

This nonwoven fabric-like fibrous structure was formed. When the obtained fiber structure was measured with a scanning electron microscope ("S-2400" manufactured by Hitachi, Ltd.), fibers with a fiber length of less than 100 µm were not observed. The scanning electron micrographs of the surface of the obtained fiber structure are shown in Fig. 7 and Fig. 8 .

Example 5

Except that the voltage was 30 kV and the distance from the discharge nozzle 1 to the fibrous material collecting electrode 5 was 10 cm, the same operation as in Example 4 was performed to form a nonwoven fabric-like fibrous structure. In the same manner as in Example 1, the resulting fibrous structure was subjected to the non-melting and calcining steps. The obtained fibrous structure had flexibility and an average fiber diameter of 0.5 μm.

This nonwoven fabric-like fibrous structure was formed. When the obtained fiber structure was measured with a scanning electron microscope ("S-2400" manufactured by Hitachi, Ltd.), fibers with a fiber length of less than 100 µm were not observed. The scanning electron micrographs of the surface of the obtained fiber structure are shown in Fig. 9 and Fig. 10 .

Comparative example 1

In the spinning dope, 1 part by weight of polycarbomethylsilane (molecular weight 3500, manufactured by Aldrich) and 9 parts by weight of dichloromethane (manufactured by Wako Pure Chemical Industries, Ltd., special grade) were used, and the same procedure as in Example 1 was carried out except that The operation failed to obtain a fibrous structure, and a granular solid was obtained.

Comparative example 2

As the spinning stock solution, 1 part by weight of polycarbomethylsilane (molecular weight: 3500; manufactured by Aldrich), 8 parts by weight of dichloromethane (manufactured by Wako Pure Chemical Industries, Ltd., special grade), tetrabutoxytitanium (manufactured by Wako Pure Chemical Industries, Ltd.) Co., Ltd.) except that the same operation as Comparative Example 1 was carried out, but a fibrous structure could not be obtained, and a granular solid was obtained.

Comparative example 3

As the spinning stock solution, 9.9 parts by weight of polycarbomethylsilane (molecular weight 3500; manufactured by Aldrich), 90 parts by weight of dichloromethane (manufactured by Wako Pure Chemical Industries, Ltd., special grade), polyethylene glycol (molecular weight 4 million, Wako Junyaku Kogyo Co., Ltd.) was prepared in the same manner as in Comparative Example 1 except that a solution having a composition of 0.1 parts by weight was used to obtain a fibrous nonwoven fabric. The non-woven fabric was heated up to 200°C in the air (heating rate of 10°C/min), kept for 1 hour, and then heated to 1000°C (heating rate of 2°C/min) in a nitrogen atmosphere, and kept for 3 hours , let cool to room temperature. The obtained fiber structure was thick, and the average fiber diameter was 5 m or more. A scanning electron micrograph of the surface of the obtained fiber structure is shown in FIG. 11 .

Claims (16)

1. inorganic fiber, it is made of silicon, carbon, oxygen, transition metal in fact, and fibre diameter is 2 μ m or below the 2 μ m, and fibre length is 100 μ m or more than the 100 μ m.

2. the described inorganic fiber of claim 1, wherein, the surface texture of fiber has a plurality of recesses that diameter is 0.01～0.2 μ m, and this recess accounts for 10～95% of fiber total surface area.

3. the described inorganic fiber of claim 1, wherein, above-mentioned transition metal is titanium and/or zirconium.

4. the described inorganic fiber of claim 1, wherein, the mol ratio of silicon and transition metal is 100/1～1/10.

5. fiber construct, it contains the described fiber of claim 1 at least.

6. the described fiber construct of claim 5, wherein, the described fiber of claim 1 accounts for 100%.

7. the manufacture method of fiber construct, this method has following steps: silicone based macromolecule, fibre forming property organic polymer and transistion metal compound three are dissolved in solvent, the step of preparation solution; With the step of above-mentioned solution by the method for electrostatic spinning spinning; Obtain being accumulated in the step of the precursor fiber structure on the collector electrode substrate by above-mentioned spinning; Above-mentioned precursor fiber structure is carried out not melt processed, obtain the step of fusion-free fibre structure; Then calcine this fusion-free fibre structure, obtain the step of inorganic fiber structure.

8. the described manufacture method of claim 7, wherein, above-mentioned transistion metal compound is titanium compound and/or zirconium compounds.

9. the described manufacture method of claim 7, wherein this silicone based macromolecule contains the repetitive of following general formula (1) expression,

(in the formula R and R ' are independently selected from hydrogen atom, carbon number respectively be 1～10 low alkyl group, phenyl).

10. the described manufacture method of claim 7, wherein, silicone based macromolecule is 100/1～1/10 with the mol ratio of mixing of transistion metal compound.

11. the described manufacture method of claim 7, wherein, the fibre forming property organic polymer is a polyethylene glycol.

12. the described manufacture method of claim 11, wherein, the molecular weight of above-mentioned polyethylene glycol is more than 50,000 or 50,000.

13. the described manufacture method of claim 11, wherein, the weight % that is dissolved with the polyethylene glycol in silicone based macromolecule, fibre forming property organic polymer and transistion metal compound three's the solution is 0.1～20%.

14. the described manufacture method of claim 7 wherein contains non-polar solven as above-mentioned solvent.

15. the described manufacture method of claim 14, wherein above-mentioned solvent contains the halogen solvent.

16. the described manufacture method of claim 15, wherein above-mentioned solvent is a carrene.

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